The present invention relates to a chemical mechanical polishing aqueous dispersion preparation set, a method of preparing a chemical mechanical polishing aqueous dispersion, a chemical mechanical polishing aqueous dispersion, and a chemical mechanical polishing method.
In recent years, planarization technology utilizing chemical mechanical polishing has attracted attention along with an increase in the degree of integration of semiconductor devices and development of multi-layer interconnect technology. A chemical mechanical polishing aqueous dispersion used for chemical mechanical polishing normally contains abrasive grains as an abrasive agent. Various abrasive grains have been proposed. Examples of the abrasive grains include inorganic particles such as fumed silica, colloidal silica, alumina, and cerium oxide, organic particles such as polymethyl methacrylate, organic-inorganic composite particles prepared by physically or chemically bonding inorganic particles and organic particles, and the like (see JP-A-2003-289055, for example).
A chemical mechanical polishing aqueous dispersion optionally contains various components such as an oxidizing agent, an organic acid, and a surfactant in addition to abrasive grains. A related-art chemical mechanical polishing aqueous dispersion has a problem in that abrasive grains aggregate during long-term storage due to poor dispersion stability of the abrasive grains, for example. A chemical mechanical polishing aqueous dispersion in which abrasive grains aggregate and precipitate affects chemical mechanical polishing performance. For example, an interconnect portion may be polished to a large extent so that a depression referred to as dishing or erosion may occur. A surface defect referred to as a scratch or the like may also occur.
A chemical mechanical polishing aqueous dispersion with constant quality cannot be provided if the abrasive grains aggregate. In particular, such a problem occurs to a large extent when providing a chemical mechanical polishing aqueous dispersion in a concentrated state. Therefore, an improvement has been desired.